At present, all suction cups on the market are of a structure with unadjustable suction force. For example, it is common to pull the handle at the center of a rubber bottom base backwards, so that a suction effect is generated between the suction cup and the suction surface. When installing a suction cup which requires to be additionally connected to the matched wire or other products, such suction cup is required to be connected to the corresponding product first and then fastened together therewith on a wall by suction. Operation of such a suction cup is often carried out repeatedly due to inaccurate alignment. Moreover, it is difficult to install the product to be connected due to its weight and volume, or it may require two people to work together. Also, the repeated operation requires the entire suction cup to be disassembled for re-installation every time. As a result, the operation is very inconvenient.